Re: [PATCH 2/2] target/i386/sev: Use local variable for kvm_sev_launch_measure

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Dov Murik (dovmurik@linux.ibm.com) wrote:
> The struct kvm_sev_launch_measure has a constant and small size, and
> therefore we can use a regular local variable for it instead of
> allocating and freeing heap memory for it.
> 
> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  target/i386/sev.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 0062566c71..eede07f11d 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -729,7 +729,7 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>      SevGuestState *sev = sev_guest;
>      int ret, error;
>      g_autofree guchar *data = NULL;
> -    g_autofree struct kvm_sev_launch_measure *measurement = NULL;
> +    struct kvm_sev_launch_measure measurement = {};
>  
>      if (!sev_check_state(sev, SEV_STATE_LAUNCH_UPDATE)) {
>          return;
> @@ -743,23 +743,21 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>          }
>      }
>  
> -    measurement = g_new0(struct kvm_sev_launch_measure, 1);
> -
>      /* query the measurement blob length */
>      ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_MEASURE,
> -                    measurement, &error);
> -    if (!measurement->len) {
> +                    &measurement, &error);
> +    if (!measurement.len) {
>          error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",
>                       __func__, ret, error, fw_error_to_str(errno));
>          return;
>      }
>  
> -    data = g_new0(guchar, measurement->len);
> -    measurement->uaddr = (unsigned long)data;
> +    data = g_new0(guchar, measurement.len);
> +    measurement.uaddr = (unsigned long)data;
>  
>      /* get the measurement blob */
>      ret = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_MEASURE,
> -                    measurement, &error);
> +                    &measurement, &error);
>      if (ret) {
>          error_report("%s: LAUNCH_MEASURE ret=%d fw_error=%d '%s'",
>                       __func__, ret, error, fw_error_to_str(errno));
> @@ -769,7 +767,7 @@ sev_launch_get_measure(Notifier *notifier, void *unused)
>      sev_set_guest_state(sev, SEV_STATE_LAUNCH_SECRET);
>  
>      /* encode the measurement value and emit the event */
> -    sev->measurement = g_base64_encode(data, measurement->len);
> +    sev->measurement = g_base64_encode(data, measurement.len);
>      trace_kvm_sev_launch_measurement(sev->measurement);
>  }
>  
> -- 
> 2.25.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK